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Warmer winters in Norway seem to be causing a decline in lemming populations, according to a new study, and researchers say the decline of the rodent is having a cascading effect. Lemming predators, like foxes and owls, have been forced to hunt different prey in what researchers call a clear-cut example of how global warming can have a disruptive impact on entire ecosystems.

Lemming populations throughout Scandinavia tend to explode naturally every three to five years, causing huge numbers to go in search of food. Occasionally this leads the rodents to jump into water and swim to new pastures new—the origin of the myth that lemmings commit mass suicide. When lemmings boom, they’re hard to miss. Norwegians have had to use snowplows to clear the squashed rodents off the roads [National Geographic News]. But the study of lemming populations during the last four decades found no population explosions since 1994.

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A new study of the prairie vole, a rodent species famed for its monogamous ways, has shown that the vole’s brain chemistry changes when its mate is taken away, and that it loses some of its vim and vigor. Researchers compared the behavior of males who were separated from either their mates or their siblings, and found that those voles who had lost their loyal mates were passive and unresponsive–maybe even depressed.

Prairie voles are one of the few mammals that are generally monogamous; the mates form life-long bonds and rear their pups together. In the new study, researchers subjected all the male voles to stress tests, like dunking them in basins of water and holding them suspended by their tails, and found that the voles whose mates had been spirited away put up less struggle. In the water, for example, they floated listlessly instead of paddling for their lives. These voles “basically were passive — they gave up,” [study coauthor Larry] Young said. “I would be hesitant to say that these animals were depressed, but their behavior is reminiscent of what you would see in a depressed person” [HealthDay News].

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The trick to keeping organs working well into old age might be taking out the trash, according to a study in Nature Medicine [subscription required]. Researchers led by Ana Maria Cuervo of Yeshiva University in New York have slowed the aging process in the livers of mice by tinkering with a system that recycles the damaged proteins hanging around in a cell.

Molecules responsible for “chaperone-mediated autophagy“ handle about 30 percent of the cells’ damaged proteins, escorting them to inner cell structures called lysosomes, where enzymes break the proteins down. Studies by Cuervo have shown that the disposal system becomes less efficient as cells grow older. They’ve also pinpointed the reason for the age-related decline — a loss of receptors on the surface of the lysosomes that causes a buildup of damaged proteins in the cell [U.S. News & World Report].

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